The present invention relates to an image-recording apparatus and an image forming apparatus, each of which employs an opt-electronic converting element.
In recent years, as a result of a progressive trend of adding multi-functional features to an image forming apparatus, some image forming apparatus is provided with an image reading apparatus that converts an image, projected from a subject, such as a document, etc., by irradiating light onto it, to electronic signals, in order to acquire image data. Such the image reading apparatus employs an opt-electronic converting element, such as a CCD (Charge Coupled Device), etc., for converting an optical image to analogue image signals, and is provided with a electronic circuit that further converts the analogue image signals to digital image signals so as to acquire the image data.
Since the waveform of the analogue image signals, acquired by the opt-electronic converting element, directly represents information of the image, there has been a problem that the waveform of the analogue image signals, outputted from a circuit including the opt-electronic converting element for generating the analogue image signals, the circuit for converting the analogue image signals to the digital image signals and a circuit for driving such the circuits, is distorted by receiving influences of noises generated by an electric power source for supplying a constant voltage and other noises generated by peripheral devices.
As a countermeasure for the abovementioned problem, a primary battery that generates relatively little noise, such as an alkaline cell, a mercury cell, a lithium cell, etc., and a secondary battery that is rechargeable for repeated uses, such as a nickel hydrogen cell, a lithium polymer cell, etc., have been employed as electric power sources exclusively used for such the circuit, in order to reduce the influence of the noise introduction. Further, to reduce an amount of noises transmitting to the low-voltage driving element, a method for shortening the power supplying line by distributing layer-built polymer cells, serving as the secondary battery, in the vicinity of the circuit element has been disclosed (for instance, set forth in Patent Document 1).
[Patent Document 1]                Tokkaihei 11-27859 (Japanese Non-Examined Patent Publication)        
According to the conventional method mentioned in the above, however, when the primary battery is employed as the power source for the opt-electronic converting element, the circuit for converting the analogue image signals to the digital image signals and a circuit for driving such the circuits, it is impossible to reuse such the primary battery by resuming its original state after the primary battery is once discharged. Accordingly, it is necessary to frequently change the primary battery every time when it has discharged, resulting in increase of costs and labors for its maintenance management. In addition, when the secondary battery is employed, there has been another problem that it takes much time to charge the-secondary battery and a complicated charge-discharge controlling circuit becomes necessary, resulting in a large sized apparatus and a considerable increase of its cost. Therefore, such the conventional apparatus are not easy and friendly usable for the user.
Incidentally, as a technology developed recently, an electric double layer capacitor has become the focus of engineer's attention as a charged power source to be utilized for a starting power source of a motor, an illumination device powered by solar cells. The electric double layer capacitor has such excellent features that a huge amount of electrostatic capacity in a unit of several farads (F) can be attained, and it can be fully charged in a short time period without preparing a specific charge-discharge controlling circuit.